On Tue, 10 Sep 2013, Tom Gundersen wrote:
> Support for specifying soft dependencies in the modules themselves was
> introduced in commit 7cb14ba.
>
> In Arch we have always been shipping a module.d(5) fragment ordering ohci/uhci
> after ehci. If this ordering is really necessary, it would be great to move it
> to the kernel and getting the correct fragment generated by depmod.
The ordering is more of a recommendation than a necessity. Systems
should work oksy if the modules are loaded in the wrong order.
The only issue if the drivers are loaded in the wrong order is that
full- and low-speed devices will end up being detected and enumerated
twice, with a disconnection in between. This can result in
disconcerting messages appearing in the system log.
In theory, it is possible for a problem to arise. For example, suppose
a full-speed flash drive is plugged in when the system starts up.
When uhci-hcd or ohci-hcd gets loaded, the drive will be detected and
it may even be mounted. Then when ehci-hcd loads, the drive will get
disconnected and reconnected. Any open file references to the original
mount will be orphaned.
> Signed-off-by: Tom Gundersen <teg@xxxxxxx>
> Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> ---
> drivers/usb/host/ohci-hcd.c | 1 +
> drivers/usb/host/uhci-hcd.c | 1 +
> 2 files changed, 2 insertions(+)
>
> diff --git a/drivers/usb/host/ohci-hcd.c b/drivers/usb/host/ohci-hcd.c
> index 8f6b695..783b50a 100644
> --- a/drivers/usb/host/ohci-hcd.c
> +++ b/drivers/usb/host/ohci-hcd.c
> @@ -1171,6 +1171,7 @@ EXPORT_SYMBOL_GPL(ohci_init_driver);
> MODULE_AUTHOR (DRIVER_AUTHOR);
> MODULE_DESCRIPTION(DRIVER_DESC);
> MODULE_LICENSE ("GPL");
> +MODULE_SOFTDEP("pre: ehci_hcd");
>
> #if defined(CONFIG_ARCH_SA1100) && defined(CONFIG_SA1111)
> #include "ohci-sa1111.c"
> diff --git a/drivers/usb/host/uhci-hcd.c b/drivers/usb/host/uhci-hcd.c
> index 4a86b63..c2babf3 100644
> --- a/drivers/usb/host/uhci-hcd.c
> +++ b/drivers/usb/host/uhci-hcd.c
> @@ -937,3 +937,4 @@ module_exit(uhci_hcd_cleanup);
> MODULE_AUTHOR(DRIVER_AUTHOR);
> MODULE_DESCRIPTION(DRIVER_DESC);
> MODULE_LICENSE("GPL");
> +MODULE_SOFTDEP("pre: ehci_hcd");
Where is MODULE_SOFTDEP defined? It isn't mentioned in any .h files in
my kernel tree.
Alan Stern
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